Circuit interrupter with contact actuating lever arm adjusting means

ABSTRACT

A circuit interrupter having relatively movable contacts, means for moving the contacts between open and closed positions which means include a support arm for the movable contact, a rotatable operating shaft, a drive structure between the shaft and the arm including a connecting link and a member extending substantially radially from the shaft and fixedly mounted thereon, the link and the member being pivotally connected, adjustable means for pivotally mounting the link on the member and comprising an elongated slot in the member and an aperature in the link which is aligned with the slot, a nut and bolt assembly extending through the slot and aperture and a bushing mounted on the bolt and within the aperture, the bushing having a cylindrical surface and having tapered annular ridges at each end thereof, whereby upon tightening of the nut and bolt assembly the ridges bite into the bifurcated portion of the member and thereby prevent movement of the nut and bolt assembly with respect to its desired location in the slot.

United States Patent Bould et al.

[ Aug. 28, 1973 CIRCUIT INTERRUPTER WITH CONTACT Primary Examiner-Herman J. Hohauser ACTUATING LEVER ARM ADJUS G Assistant Examiner-Robert A. Vanderhye MEANS Attorney- A. T. Stratton, L. P. Johns et a].

{57 ABSTRACT Inventors: Fred Bould, Swissvale; Norman A circuit interrupter having relatively movable con- Daviess Traffod both of tacts, means for moving the contacts between open and [73] Assignee: Westinghouse Electric Corporation, closed positions which means include a support arm for Pittsburgh, the movable contact, a rotatable operating shaft, a drive structure between the shaft and the arm including Flled: July 1972 a connectin link and a member extending substantially g [21] Appt NOJ 271,426 radially from the shaft and fixedly mounted thereon,

the link and the member being pivotally connected, adjustable means for pivotally mounting the link on the [52] US. Cl 200/153 II, 200/153 SC, 74/522 member and comprising an elongated slot in the CI 3/46, Holh 3/30 8 1/24 her and an aperature in the link which is aligned with [58] Field of Search 200/153 SC, 153 H, the Slot a nut d b assembly extending through the 200/162, 166 M; 74/522, 525, 510 slot and aperture and a bushing mounted on the bolt and within the aperture, the bushing having a cylindri- [56] References and cal surface and having tapered annular ridges at each UNITED STATES PATENTS end thereof, whereby upon tightening of the nut and 1,435,720 11/1922 McGahey 74/525 x b0!t assembly the ridges bite into the bifurcated Portion l,600,822 9/1926 Hedgcock 74/522 f the mem er and thereby prevent movement of the 3,236,967 2/1966 Bottonari et al. 200/153 SC UX nut and bolt assembly with respect to its desired loca- 3,684,848 8/l972 Davies 200/153 SC {ion in the slot,

16 Claims, 12 Drawing Figures SHEEI 1 BF 8 FIG.

FIG. 2

PATENTED MIG 28 I973 FIG. 3

PATENTEDmszs mm 3.755 639 saw u or a PATENTEU MIG 2 8 M3 SHEEI 7 OF 8 CIRCUIT INTERRUPTER WITH CONTACT ACTUATING LEVER ARM ADJUSTING MEANS CROSS-REFERENCE TO RELATED APPLICATIONS Certain parts of the circuit interrupter disclosed herein are disclosed in copending applications to Norman Davies, entitled Circuit Interrupter" Ser. No. 106,328, filed Jan. 14, 1971, now U.S. Pat. No. 3,684,848 and entitled Circuit lnterrupter With Motor Operated Spring Charging Means Including Two Rachets and Two Pawls", Ser. No. 106,330, filed Jan. 14, 1971, now U.S. Pat. No. 3,652,815.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to circuit interrupters and more particularly it pertains to contact adjusting means for disconnect switches and similar devices.

2. Description of the Prior Art Circuit interrupters of prior construction, among other things, comprise a stored energy overcenter spring operating means for operating the interrupter between open and close positions. Inasmuch as most circuit interrupters comprise a plurality of movable contacts which cooperate with stationary contacts, it is desirable that all of the contacts be aligned to make and break a circuit simultaneously. Moreover, where after substantial use the contacts are no longer synchronized for simultaneous making and breaking of a circuit, it is desirable to provide means for readily and permanently adjusting the operating mechanism of each contact. Heretofore, most circuit interrupters have not been provided with adequate means for easily making permanent adjustments.

Associated with the foregoing has been an inherent problem of manufacturing tolerances. The problem of achieving synchronized operation of the contacts is aggravated by the tendency to manufacture assembled parts with wide tolerances. Indeed, with the present invention, it has been found more satisfactory to provide suitable adjusting means than to use closer tolerances.

SUMMARY OF THE INVENTION It has been found in accordance with this invention that the disclosed circuit interrupter with suitable adjusting means satisfies prior existing problems by providing stationary contacts and movable contacts, means for opening and closing the contacts including an operating shaft supported for rotation between open and closed positions, the means also including a linkage between the operating shaft and each movable contact, the linkage including a member comprising two spaced apart portions and a link, the member extending substantially radially of the shaft and being pivotally connected to one end of the link, the other end of the link being pivotally connected to a movable contact supporting lever, the spaced apart portions of the member having aligned slots and the link having an aperture aligned between the slots, adjustable means for pivotally mounting the link and member together and comprising a bushing and a nut and bolt assembly, the bolt extending through the openings and the aperture and having the bushing mounted thereon, the bushing extended through the aperture in the link, and the bushing having an annular tapered ridge on each end thereof, whereby upon tightening of the nut and bolt assembly the annular tapered ridge bites into the spaced apart portions of the member with the bolt located in the desired position within the elongated slots.

The advantage of the device of this invention is that it provides for an expedient and permanent means for adjusting the position of a movable contact with respect to an operating shaft; and, more particularly, it enables the manufacture of parts for a circuit interrupter based upon manufacturing tolerances which are not as close as would be otherwise required, whereby a cost improvement is achieved in the device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view, with parts broken away, of a circuit interrupter constructed in accordance with the principles of this invention;

FIG. 2 is a front view of the circuit interrupter illustrated in FIG. 1;

FIG. 3 is a sectional view taken generally along the line IIIIII of FIG. 2;

FIG. 4 is a front view, with parts broken away, illustrating the operating mechanism shown in FIG. 2;

FIG. 5 is a sectional view, taken generally along the line VV of FIG. 4, with the parts being shown in the spring discharged closed position;

FIG. 6 is a view of certain parts disclosed in FIG. 5, with the parts being shown in the spring-charged closed position;

FIG. 7 is a view similar to FIG. 5 with the parts being shown in the spring discharged open position;

FIG. 8 is a view similar to FIG. 6 with the parts being shown in the spring-charged open position;

FIG. 9 is a plan view, taken on the line IX-IX of FIG. 3;

FIG. 10 is a side elevational view taken on the line X--X of FIG. 9;

FIG. 11 is an enlarged sectional view taken on the line XI-XI of FIG. 11; and

FIG. 12 is a plan view partly in section of another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, there is shown, in FIGS. 1 and 2, a circuit interrupter 7 comprising support means 9 and a circuit-interrupter structure 11 supported on the support means 9. The support means 9 comprises backplate means 13 and a pair of side plate means 15, connected to the backplate means 13. A pair of elongated channel members 17 are supported on the side plate means 15 for supporting the terminals of the circuit interrupter.

The circuit interrupter structure 11 comprises three stationary contacts 21 (FIGS. 2 and 3) supported on one of the back support channel members 17. A separate movable contact arm 25 is provided to cooperate with each of the stationary contacts 21. Each of the contact arms 25 comprises a pair of spaced contact members (FIG. 2) that comprise contact portions that engage the opposite sides of the associated stationary contact 21 in the closed position of the contacts. Each of the contact arms 25 is supported for pivotal movement on a separate conducting terminal 27 by means ofa pivot pin 29. Each of the terminals 27 is supported on an insulating support 31 that is, in turn, supported on one of the channel support members 17. In each pole unit, a terminal plate 33 is connected to the contact 21 and a terminal plate 35 is connected to the terminal 27 to enable connection of the pole unit in an electric circuit.

In each pole unit, an elongated link 37 (FIG. 3) is pivotally connected at one end thereof to the movable contact arms 25 by means of a pivot pin 39 and at the other end thereof to a pair of spaced members 41 by means of a pivot pin 43. Each of the members 41 is an integral part of an elongated operating shaft 45. As can be understood with reference to FIGS. 2 and 3, the op erating shaft 45 is supported on the sideplate means 15 for rotational movement about the elongated axis thereof. The circuit interrupter is shown in full lines in FIG. 3 in the closed position. Upon counterclockwise movement of the operating shaft 45 to the open position shown in broken lines, the three links 37 of the three pole units are moved to move the contact arms 25 to the open positions shown in broken lines. Reverse or clockwise movement of the operating shaft 45 from the position shown in broken lines operates through the links 37 to move the three contact arms 25 from the open positions shown in broken lines to the closed position shown in full lines.

An operating mechanism 49 (FIGS. 2, 4 and is provided for operating the operating shaft 45 between the closed and open positions. The operating mechanism 49 comprises drive means 51, an overcenter spring structure 53, a latch linkage 55, a latch structure 57, and a trip device 59.

The drive means 51 comprises a drive member 61 supported on the operating shaft 45 for rotational movement relative to the operating shaft 45. The drive member 61 is provided with an opening 63 for receiving a crank rod 65 that can be placed into the opening 63 in order to crank the drive member 61 between the open and closed positions.

The overcenter spring structure 53 comprises an elongated rod 67 that extends at one end thereof through an opening 69 in a stationary plate 71 that is connected on the side plate means 15. A pin 73 and washer 75 are supported on the rod 67. An overcenter spring 77 is supported on the rod 67 between the washer 75 and the plate 71. The rod 67 is pivotally connected at the other end thereof to a member 79 by means of a pin 81. As can be understood with reference to FIG. 4, the pin 81 extends out through opposite sides of the member 79. The member 79 is supported on the operating shaft 45 for rotational movement relative to the operating shaft 45. A member 85 is fixedly secured to the operating shaft 45. The member 85 is provided with extension 89 at the other side of the operating shaft 45. The member 85 is also provided with an integral extension or toggle link 91 that serves as one link of a toggle of the latch linkage 55 in a manner to be hereinafter described. The other toggle link is a member 93 that is pivotally connected at one end thereof to the part 91 by means of a pivot pin 95 and at the other end thereof to an elongated link 97 by means of a pivot pin 99.

The link 97 is pivotally supported, intermediate the ends thereof, on a stationary support bracket 101 by means ofa pin 103 (FIG. 5). The support bracket 101 is suitably secured to the side plate means 15. The link 97 is provided with a notch 105 at the upper end thereof that engages a roller 107 of a roller latch 109. The roller latch 109 is pivotally supported on the bracket by means ofa pin 1 11. The roller latch 109 is provided with a roller 113 at the other end thereof that engages in a notch 11S ofa latchmember 117 that is pivotally supported on the bracket 101 by means of a pivot pin 119. A torsion spring 121 biases the roller latch 209 in a clockwise direction to the latching position seen in FIG. 5, and a torsion spring 123 biases the latch 117 in a counterclockwise direction to the latching position seen in FIG. 5. The latch 117 is provided with an extension 127 that can be manually moved to pivot the latch 117 in a clockwise direction in order to operating the interrupter in a manner to be hereinafter described. The extension 127 may also be actuated by the electromagnetic trip 59 that comprises a plunger 129 that is raised when the electromagnet 59 is cnergized to thereby automatically move the latch 117 in a clockwise (FIG. 5) direction to the actuated position.

The circuit interrupter is shown in the spring discharged closed position in FIGS. 1-5. In order to operate the circuit interrupter to the open position, the crank rod 65 is placed in the opening 63 (FIGv 5) of the drive member 61, and the crank rod 65 is manually cranked from the spring discharged closed position seen in FIG. 5 to the spring charged closed position seen in FIG. 6. During this movement, an extended part 131 of the drive member 61 engages the pin 81 (FIGS. 4 and 5) to drive the intermediate member 79 and spring rod 67 from the spring discharged closed position seen in FIG. 5 to the overcenter spring charged closed position seen in FIG. 6. During this movement, the spring 77 is charged and near the end of this movement, the spring rod 67 passes overcenter relative to the axis of the operating shaft 45, whereupon the spring 77 starts to discharge driving the pin 81 against the extended part 87 of the member to bias the member 85 and the operating shaft 45, to which the member 85 is secured, in a counterclockwise (FIG. 6) direction toward the open position seen in FIG. 7.

The overcenter spring structure 53 is latched in this spring charged closed position (FIG. 6) by the latch linkage 55 (FIG. 5) which prevents counterclockwise rotation of the operating shaft 45 and by the latch structure 57 which latches the latch linkage 55 in the position seen in FIG. 5. In this position, it is noted that a toggle 91, 93 of the latch linkage 55 is underset or collapsed in a downward (FIGS. 5 and 6) direction. The parts will remain in the spring charged closed position seen in FIG. 6 until release of the latch linkage 55. Thus, energy is stored for a closing operation.

In order to close the circuit interrupter with the spring 77 in the charged position seen in FIG. 6, the latch member 117 (FIG. 5) is pivoted in a clockwise (FIG. 5) direction manually, by lifting the part 127, or electromagnetically by operation of the electromagnet 59 to move the plunger 129 upward to lift the part 127. During this movement, the latch 117 moves to release the roller 113 from the notch I15, permitting the roller latch 109 to rotate in a counterclockwise (FIG. 5) direction about the pin 111. This movement permits the roller 107 to move out of the notch 105, permitting the elongated link 97 to pivot in a counterclockwise direction about the pivot pin 103. This movement releases the toggle 91, 93 to release the operating shaft 45, whereupon the charged spring 77 discharges driving the rod 67 from the spring charged closed position seen in FIG. 6 to the spring discharged open position seen in FIG. 7 with the pin 81 (FIGS. 4, 6 and 7) operating against the extended part 87 of the member 85 to drive the member 85, and the operating shaft 45 to which the member 85 is secured, in a counterclockwise direction from the spring charged closed position seen in FIG. 6 to the spring discharged open position seen in FIG. 7.

During that movement, the operating shaft 45 rotates from the closed position seen in full lines in FIG. 3 to the open position seen in broken lines in FIG. 3 moving the links 37 of the three pole units to the position seen in broken lines in FIG. 3 to thereby move the three contact arms 25 to the open position seen in broken lines in FIG. 3. Upon movement of the parts from the spring charged closed position seen in FIG. 6 to the spring discharged open position seen in FIG. 7, the toggle 91, 93 is moved from the collapsed or downward underset position seen in FIG. 6 to the collapsed or upward underset position seen in FIG. 7 during which movement the link 97 is moved first in a counterclockwise direction as the toggle 91, 93 moves to the erected position and then in a clockwise direction as the toggle 91, 93 collapses to the upward undersetposition seen in FIG. 7. This movement automatically resets the toggle link 97 in the position seen in FIG. 7, and the springs 121, 123 automatically reset the latches 109, 117, respectively, in the latching positions, seen in FIG. 7.

In order to manually operate the circuit interrupter from the spring discharged open position seen in FIG. 7 to the spring discharged closed position seen in FIG. 5, the circuit interrupter is first operated to the spring charged open position seen in FIG. 8. With the circuit interrupter in the position seen in FIG. 7, the crank 65 is moved from the position seen in FIG. 7 to the position seen in FIG. 8. During this movement, the drive member 61 is moved with the projecting portion 133 thereof operating against the pin 81 (FIGS. 7 and 4) to drive the member 79 and the rod 67 from the spring discharged open position seen in FIG. 7 to the spring charged open position seen in FIG. 8. During this movement, the'rod 67 goes overcenter relative to the axis of the operating shaft 45 and the spring77, which is charged during the early part of this movement, starts to discharge forcing the rod 67 and member 79 in a counterclockwise (FIG. 8) direction. This movement is limited by the engagement of the pin 81 with the projecting part 89 of the member 85, that is secured to the operating shaft 45, and with the latch linkage 55 latched by means of the latch structure 57, the parts are latched in the stored energy spring charged open positions seen in FIG. 8.

In order to release the stored energy and close the circuit breaker, the part 127 of the latch member 117 is lifted, either manually or electromagnetically, to rotate the latch 117 is a counterclockwise direction to release the roller 113 from the notch 115 to release the roller latch member 109, permitting counterclockwise movement of the roller latch member 109. Upon release of the roller latch member 109 the roller 107 moves out of the notch 105 of the link 97 to permit counterclockwise movement of the link 97. This movement permits the toggle 91, 93 to move from the upward underset position seen in FIG. 7 to thereby permit clockwise movement of the operating shaft 45. The spring 77 discharges and moves the rod 67 from the spring charged open position seen in FIG. 8 to the spring discharged closed position seen in FIG. 5. During this movement, the pin 81, operating against the part 89 of the member 85, drives the member 85 and the operating shaft 45 from the spring charged open position seen in FIG. 8 to the spring discharged closed position seen in FIG. 5. During this movement, the operating shaft 45 rotates in a clockwise (FIG. 3) direction to move the links 37 and the three contact arms 25 from the open position seen in broken lines in FIG. 3 to the closed position seen in full lines in FIG. 3.

During the movement to the closed position, the movement of the operating shaft 45, operating through the toggle 91, 93 first moves the link 97 in a counterclockwise direction as the toggle 91, 93 moves to the erected position and then the link 97 is moved in a clockwise direction as the toggle 91, 93 moves to the downward underset position seen in FIG. 5. This movement moves the link 97 to the latching position seen in FIG. 5, and the springs 121, 123 operate to automatically reset the roller latch member 109 and the latch member 117 in the latched position seen in FIG. 5. The circuit interrupter may then be operated to the spring charged closed position seen in FIG. 6 and to the spring discharged open position seen in FIG. 7 in the same manner as was hereinbefore described.

In accordance with this invention, in order to facilitate the installation and maintenance of a proper linkage between the operating shaft 45 and the movable contact arm 25, adjustable means are provided as shown in FIGS. 9-11 for pivotally clamping the member 41 to the link 37. The adjustable means generally indicated at 129 comprise a bushing 131 (FIG. 11) and clamping means associated therewith such as a bolt 133 and a nut 135. As shown for the embodiment of FIGS. 9-11 the link 37 extends between the right ends of the members 41 where it is pivotally attached to the members by the adjustable means 129.. For that purpose the link 37 is provided with an aperture 137 (FIG. 11) in which the bushing 137 is disposed. The aperture 137 is aligned with similar openings 139 in the spaced members 41 and the bolt 133 extends through the aligned openings and aperture.

The shape of the aperture 137 corresponds to that of the peripheral surface of the bushing 133 and is preferably round. However, the openings 139 are elongated (FIG. 10) and ofa width sufficient to receive the shank of the bolt 133. More particularly, the elongated openings 139 have axes substantially parallel to each other and parallel to the axes of the members 41. In this manner, the precise location of the bolt 133 in the openings 139 may be ascertained by suitable procedures which enable the movable contact arm to be positioned with respect to the shaft 45 and at the same time providing proper adjustment for the several movable contacts involved.

Once the precise position of the bolt 133 within the elongated openings or slots 139 is obtained the nut is tightened on the bolt in order to clamp the spaced members 41 against opposite ends 141 of the bushing 131. For that purpose, the bushing l31is slightly longer than the width of the link 37 and each end 141 is provided with pointed projection means such as annular ridges or sharp portions 143 which are pressed into the surface portions of the members 41 above and below the elongated openings 139. More particularly, as the nut 135 is tightened on the bolt 133 the spaced mem bers 41 are tightened against the pointed projection means or ridges 143 where they are retained by the nut and bolt assembly in fixed positions. Thus, the link 37 is free to rotate around bushing which is seated in the circular aperture 137.

Although the pointed projection means are preferably a singular annular ridge 143 in each end 141 of the bushing 133, the means may comprise another configuration such as a plurality of concentric annular ridges 143, or arcuate segments of one or more ridges disposed at spaced intervals either circumferentially or radially of each other with respect to the center of the bushing 133. in addition, the pointed projection means may comprise non arcuate randomly disposed tapered portions of the bushing 131 which upon clamping of the nut and bolt assembly are embedded in or in biting engagement with the adjacent surfaces of the corresponding spaced members 41. For that purposg, the bushing 131 is comprised of a hardened metal member having a hardness greater than that of the spaced members 41 in order to facilitate the embedding of the annular ridges 143 into the members. It is noted that the annular ridges 143 are embedded into the portions of the members 41 above and below the openings 139.

As shown in FIGS. 1-11 the members 41 are mounted on the shaft 45 in a suitable manner such as by a clamping means including a bolt 145 and a nut 147 which extend between spaced clamping bars 149 of upper and lower edges of the members 41. In the alternative the arms 41 may be welded in place on the shaft 45 instead of being bolted. Another embodiment of the invention is shown in FIG. 12 in which the adjustable means includes a pair of bushings 151 and 153 having pointed projection means such as annular ridges 155 and 157, respectively. The two bushings 151 and 153 are required where instead of a pair of members 41 (FIG. 9) are provided, a single member 159 is provided and a pair of links 161 of insulating material are disposed between the bushings 151 and 153 as well as the arms 25. As shown, one end of each bushing 151, 153 is rotatably mounted in an opening 163 in each link 161 and extend through the openings, whereby upon tightening of a clamping means such as a nut and bolt assembly comprising a bolt 165 and a nut 167 the annular ridges 155 and 157 are embedded into the portions of the member 159 above and below an opening or slot 169 in the member.

The left end of the member 159 as viewed in FIG. 12 is attached to the shaft 45 in a suitable manner suchas weld 171. Or, the member may be attached in a suitable clamping manner such as a nut and bolt assembly as shown in the embodiments for FIGS. 9-11.

Accordingly, the circuit interrupter of the present invention provides means for making adjustments due to the use of wider manufacturing tolerances than have been heretofore employed, and thereby results in a cost improvement in the circuit interrupter.

What is claimed is:

1. A circuit interrupter comprising a plurality of pole units each including a stationary contact and a movable contact being mounted on a pivotally mounted arm, an operating mechanism for actuating the contact arms between open and closed positions with respect to the associated stationary contacts, said operating mechanism including a common operating shaft supported for rotation between first and second positions corresponding to the open and closed positions, respectively, of said contact arms, means connecting the operating shaft to each of said contact arms and comprising a radially extending member on the operating shaft and an insulating link, one end of the link being pivotally connected to the member and the other end of the link being pivotally connected to the arm, one of the member and link comprising a pair of spaced apart portions and the other of the member and link having an end portion disposed between the spaced apart portions, one of the member and link having aperture and the other of the member and link having an elongated opening, adjustable means for pivotally mounting the link and member together and comprising a pin-like element and a bushing structure, the bushing being located in the aperature, the pin-like element extending through the elongated opening and the bushing, the bushing structure being cylindrical and having pointed projection means on at least one end for biting into the surfaces of the spaced apart portions adjacent the elongated opening, and the adjusting means comprising clamping means associated with the pin-like element for clamping one of the member and link having the elongated opening into biting engagement with the pointed projection means, whereby the linkage between the operating shaft and the arm is adjustable to a required position within the length of the elongated opening.

2. The circuit interrupter of claim 1 in which the member or link having the aperture is comprised of an electrically insulating material.

3. The circuit interrupter of claim 2 in which the elongated opening is substantially parallel to the longitudinal axis of the other of the member and link.

4. The circuit interrupter of claim 3 in which the pinlike element and clamping means comprise a bolt and nut assembly.

5. The circuit interrupter of claim 4 in which the pointed projection means comprises at least one projecting segment having a tapered ridge.

6. The circuit interrupter of claim 5 in which the projecting segment has an arcuate shape.

7. The circuit interrupter of claim 6 in which the arcuate projecting segment is continuous.

8. The circuit interrupter of claim 6 in which the arcuate projecting segment is annular.

9. The circuit interrupter of claim 1 in which the radially extending member comprises a pair of spaced apart portions, each portion having an elongated opening substantially parallel to the axis of said portion, and the link comprising an electrically insulating material.

10. The circuit interrupter of claim 9 in which the bushing structure being cylindrical and having pointed projection means at both ends for biting into the surfaces of the spaced apart portions of the radially extending member.

11. The circuit interrupter of claim 10 in which the pin-like element and clamping means comprise a bolt and nut assembly.

12. The circuit interrupter of claim 11 in which the pointed projection means comprises at least one projecting segment having a tapered arcuate ridge.

13. The circuit interrupter of claim 12 in which there is one tapered annular ridge.

14. The circuit interrupter of claim 1 in which the link comprises a pair of spaced apart portions and composed of electrically insulating material and the member has an elongated opening substantially parallel to the axis thereof.

15. The circuit interrupter of claim 14 in which the bushing structure comprises a pair of bushings mounted on the pin-like element, one bushing being disposed between the member and one of the spaced apart portions and the other bushing being disposed between the member and the other spaced apart portion, and the end of each bushing facing the member comprising a projecting segment having a tapered ridge.

16. The circuit interrupter of claim 15 in which the projecting segment is annular.

t t t t 

1. A circuit interrupter comprising a plurality of pole units each including a stationary contact and a movable contact being mounted on a pivotally mounted arm, an operating mechanism for actuating the contact arms between open and closed positions with respect to the associated stationary contacts, said operating mechanism including a common operating shaft supported for rotation between first and second positions corresponding to the open and closed positions, respectively, of said contact arms, means connecting the operating shaft to each of said contact arms and comprising a radially extending member on the operating shaft and an insulating link, one end of the link being pivotally connected to the member and the other end of the link being pivotally connected to the arm, one of the member and link comprising a pair of spaced apart portions and the other of the member and link having an end portion disposed between the spaced apart portions, one of the member and link having aperture and the other of the member and link having an elongated opening, adjustable means for pivotally mounting the link and member together and comprising a pin-like element and a bushing structure, the bushing being located in the aperature, the pinlike element extending through the elongated opening and the bushing, the bushing structure being cylindrical and having pointed projection means on at least one end for biting into the surfaces of the spaced apart portions adjacent the elongated opening, and the adjusting means comprising clamping means associated with the pin-like element for clamping one of the member and link having the elongated opening into biting engagement with the pointed projection means, whereby the linkage between the operating shaft and the arm is adjustable to a required position within the length of the elongated opening.
 2. The circuit interrupter of claim 1 in which the member or link having the aperture is comprised of an electrically insulating material.
 3. The circuit interrupter of claim 2 in which the elongated opening is substantially parallel to the longitudinal axis of the other of the member and link.
 4. The circuit interrupter of claim 3 in which the pin-like element and clamping means comprise a bolt and nut assembly.
 5. The circuit interrupter of claim 4 in which the pointed projection means comprises at least one projecting segment having a tapered ridge.
 6. The circuit interrupter of claim 5 in which the projecting segment has an arcuate shape.
 7. The circuit interrupter of claim 6 in which the arcuate projecting segment is continuous.
 8. The circuit interrupter of claim 6 in which the arcuate projecting segment is annular.
 9. The circuit interrupter of claim 1 in which the radially extending member comprises a pair of spaced apart portions, each portion having an elongated opening substantially parallel to the axis of said portion, and the link comprising an electrically insulating material.
 10. The circuit interrupter of claim 9 in Which the bushing structure being cylindrical and having pointed projection means at both ends for biting into the surfaces of the spaced apart portions of the radially extending member.
 11. The circuit interrupter of claim 10 in which the pin-like element and clamping means comprise a bolt and nut assembly.
 12. The circuit interrupter of claim 11 in which the pointed projection means comprises at least one projecting segment having a tapered arcuate ridge.
 13. The circuit interrupter of claim 12 in which there is one tapered annular ridge.
 14. The circuit interrupter of claim 1 in which the link comprises a pair of spaced apart portions and composed of electrically insulating material and the member has an elongated opening substantially parallel to the axis thereof.
 15. The circuit interrupter of claim 14 in which the bushing structure comprises a pair of bushings mounted on the pin-like element, one bushing being disposed between the member and one of the spaced apart portions and the other bushing being disposed between the member and the other spaced apart portion, and the end of each bushing facing the member comprising a projecting segment having a tapered ridge.
 16. The circuit interrupter of claim 15 in which the projecting segment is annular. 